Using the WordPress JSON REST API in Testing Suites with Travis CI

On October 18, 2014 by Taylor Lovett

Problem:

We are writing custom endpoints and routes that extend WP API in a theme or plugin. We want to write tests for this code and run tests in Travis CI. Right now, WP API is not in WordPress core and must be included as a plugin. Therefore, we have a WordPress plugin/theme that depends on another plugin. We want to make sure all our dependencies are installed/included when we bootstrap our testing suite. WP API is not a registered Composer package.

Bad Solution #1:

Complain about WP API not being a registered Composer package. Just joking. The reason behind this is that WP API must remain backwards compatible after being included in WordPress core.

Bad Solution #2:

Include WP API in your theme/plugin as a Git submodule. Not only are Git submodules annoying but this doesn’t even make sense. Git submodules point to a specific commit. We want to just install the latest stable version which isn’t possible using submodules unless we want to manually update our submodule commit hash every time WP API is updated.

Final Solution

We need to manually include WP API in our plugin/theme but we want it up-to-date. We want to pretend WP API is a Composer package. If it’s not already there, create a folder vendor/ in the root of your project. This is the same folder that Composer will store your packages. Add vendor/ to your .gitignore since we don’t need this code in production (assuming you don’t have other packages in vendor that are needed in production).

We can execute bash scripts whenever Composer install/update is called. Let’s write a simple Bash script to clone/update WP API into vendor/. Place this code in bin/install-wp-api.sh:

composer.json defines your package as a Composer package, registers it’s dependancies, and more. As I mentioned before, we can call scripts as well. We use the pre-install-cmd hook to execute our script every time composer install is called. We use the pre-update-cmd hook to execute our script every time composer update is called. On both of these hooks we are executing our script at ./bin/install-wp-api.sh.